The invention relates to a magnetic transfer device, which uses magnetic transfer technology to write specific data or servo signals for magnetic head positioning for writing and reading of data written in the magnetic disk surface of a hard disk drive (hereafter “HDD”).
At present, magnetic disks are shipped in a state in which no information is magnetically written, and after installation in a HDD device, the necessary magnetic information is written within the HDD. In the HDD, magnetic disks are magnetically divided into concentric regions having a fixed width, called tracks, and data reading and writing is performed while causing the magnetic head to follow over these tracks. The HDD detects positional deviations of the head through magnetic signals, called servo signals, which are written on the tracks, and the head is controlled so as not to deviate from a track.
However, in order to precisely write servo signals in a concentric shape in a magnetic disk onto which nothing has been written, a device having a precise position control function is necessary; and because a mechanism requiring precise positioning is inserted into an HDD from outside, this task must be performed within a cleanroom in order to prevent intrusion of dust into the HDD. Also, several hours are required to write servo signals to tracks, which number in the hundreds of thousands on a single surface, while performing precise positioning. As stated above, this task of writing servo signals must be performed in a cleanroom for each HDD, and a high-precision device is used, resulting in increases in HDD manufacturing costs.
Technology and a device have been developed in which, by bringing into close contact with the magnetic disk a special disk for magnetic transfer called a master disk, having the above-described servo signal pattern, and applying a magnetic field from outside, the servo signal pattern is instantaneously transferred to the magnetic disk. By this means, drive manufacturing costs can be reduced, and track densities can be increased (track widths can be reduced). However, magnetic transfer is performed with the master disk brought into close contact with the magnetic disk, so that particles trapped between the two present a major problem. Trapped particles worsen the close contact between the master disk and magnetic disk and worsen the quality of transferred signals; moreover, there is the possibility of damage to the signal pattern of the master disk, and if a master disk which has once been damaged continues to be used, media with degraded transferred signal quality continue to be manufactured.
In light of the above problem, for example in Japanese Patent Laid-open No. 2005-63579, a method is disclosed in which air is blown onto and simultaneously suctioned from the surfaces of both disks before being brought into close contact; in Japanese Patent Laid-open No. 2005-169302 and in Japanese Patent Laid-open No. 2003-85936, methods are disclosed in which the surface of a master disk is cleaned using dry ice or plasma etching; and, in Japanese Patent Laid-open No. 2002-92871, a method is proposed in which a master disk is subjected to periodic ultrasonic cleaning.
On the other hand, there are very few magnetic transfer devices the transfer mechanism portion of which features prevention of the occurrence of particles while satisfying requirements for transfer performance. In a transfer mechanism portion, two holders, which grasp the master disk and a magnetic disk, are moved into and out of contact, and during transfer the two disks are placed in a space in which airtightness is maintained. Hence in order to maintain airtightness the two holders having sliding portions, and during sliding thereof, dust generation poses a problem.
In Japanese Patent Laid-open No. 2004-310809, a transfer holder of a magnetic transfer device is disclosed, which is characterized in not having a sliding portion in the above-described space in which airtightness is maintained. However, due to an elastic structure for the outer periphery of the holder, pressure is applied to the holder center portion when the master disk and magnetic disk are brought into close contact, and there is no longer space for arrangement of and rotation of a transfer magnet. Further, due to elastic deformation when pressure is applied, the precision of positioning between the disks is reduced, so that servo signals may be transferred with eccentricity, or in other ways transfer performance is necessarily sacrificed. In Japanese Patent Laid-open No. 2002-183948, a method is disclosed of bringing a plurality of positioning pins into contact with a slave holder and performing positioning, and in Japanese Patent Laid-open No. 2003-272138, a method is disclosed in which, in order to resolve the problem of adhesion of dust to surfaces in close contact, a suction passage for suction of dust is opened, and dust occurring at the time of insertion and removal of the center pin into and from the slave media and at other times is suctioned away and removed.